ambassador to libya, was killed as the american consulate came under attack in benghazi. u.s. officials confirm stevens, information officer shawn smith and two other americans were killed as they tried to evacuate staff members from the complex. >> make no mistake, we will work with the libyan government to bring to justice the killers who attacked our people. >> reporter: gunmen armed with automatic weapons stormed the consulate overnight. the mob of mostly conservative muslims was protesting an american made film that they believe insults islam's prophet muhammad. >> this is an attack that should shock the conscience of people of all faiths. >> reporter: stevens was a career diplomat who had already served to hours in lybia. >> he risked his life to stop a tyrant. then gave his life trying to help build a better libya. >> reporter: the unrest started in cairo, egypt where demonstrators scaled the wall of the u.s. embassy and tore down the american flag all in the name of religion. republican white house hopeful mitt romney accused the obama administration of sending mixed s